Mold clamping apparatus of a die casting machine and so on, a method of changing a mold in the die casting machine and so on provided with the mold clamping apparatus and a changing system of a moving die plate

ABSTRACT

(Problem to be solved) The present invention provides a die plate and a mold clamping apparatus equipped with the die plate for a die casting machine and so on capable of reducing dimensions of die height as small as possible. (Solution) A fix die plate FXPL and a moving die plate MVPL of a mold clamping apparatus on a base BS place a main mold with versatility inside, respectively. A pair of insert dies FINS and MINS is carried in to a mold opened space without disturbing tie bars TBU or TBD located in an upper portion or a side portion. The pair of insert dies are separated and fastened to each of the main mold with versatility. The die height becomes zero or very small when the moving die plate positions at a mold closing position, and as the result dimension of the mold clamping apparatus in the direction of mold opening and closing can be shortened. Also, particularly the moving die plate can be avoided to tilt.

A mold clamping apparatus of a die casting machine and so on, a method of changing a mold in the die casting machine and so on provided with the mold clamping apparatus and a changing system of a moving die plate.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a die casting machine or a plastic injection molding machine (hereinafter merely called a die casting machine and so on), and specifically relates to the die casting machine and so on provided with a mold clamping apparatus enabling dimensions as small as possible in the direction of opening and closing of a mold, and a method of changing the mold in the die casting machine and so on provided with such a mold clamping apparatus.

2. Description of the Related Art

Die casting is a molding method in which melt metal is molded into a mold which is manufactured with high dimensional accuracy. Accordingly, it has a big advantage that a molded article with a complicated shape can be molded in one process, compared with plastic forming such as forging and extruding, or cutting work. Therefore, the die casting machine is suitable for an industrial machinery which produces in low prices and in the fashion of mass production, various kinds of industrial parts and constituent elements with complicated shapes, particularly parts, members, or molded articles of constituent element such as an automotive engine that are required to increase in mechanical strength.

On the other hand, the mold of the die casting machine which is prepared for molding the various kinds of molded articles mentioned above is mostly formed in the combination of an insert die defining a cavity corresponding to the shape of each molded article and a main mold fastening and holding the insert die, mainly from the point of production cost, though the cavity can be formed with a single steel material. In the case of the plastic injection molding machine, the mold is also formed in the combination of the insert die and the main mold.

Such a main mold, therefore, can be seen as the main mold with versatility, because it is able to correspond to the insert dies for various kinds of molded articles as its function.

Also, compared with the plastic injection molding machine, the mold for the die casting machine is provided with many core cylinders in the directions of up and down, or right and left, because many cores are used for molding much more complicated molded articles.

Generally, the main mold forming a moving mold mounted on a moving die plate of the die casting machine is provided with much more core cylinders than a main mold forming a fix mold mounted on a fix mold die plate, and includes various constituent elements such as a portion of an extrusion pin for extruding a molded article and pipe lines for supply and drain of the pressurized oil to and from each the cylinder, so that it constitutes a complicated formation in which many core cylinders are mounted thereon extended in the direction of up and down, or right and left Accordingly, in case that each main mold actually fastening the insert die is mounted on the moving die plate and the fix die plate respectively, there causes a problem that at least two upper tie bars disturb the main mold when it is carried in or carried out to and from a working space for mounting, which is located between the moving die plate and the fix die plate, particularly by means of a crane.

In order to avoid such disturbance the tie bars are pulled out from both of the die plates before mold changing operation. Further it is necessary to provides cylinders used only for pulling out the tie bars in the die casting machine, which causes another problem that the dimension of the mold clamping apparatus in the direction of opening and closing of the mold must be increased to the extent of securing such a working space.

FIG. 5 is a flow chart illustrating a series of work sequences for mold changing operation in the prior art described above. As shown in FIG. 5, in the step 5 and the step 9 the tie bar is pulled out from a fix die plate and inserted therein, respectively. In the case there causes a problem that it takes considerable time to move the tie bar for pulling out the fix die plate and inserting therein because the tie bar has a large amount of weight.

Also, in the prior art the main mold and the insert die are carried in or carried out to and from the die casting machine in the state of combination, and those are attached fixedly on or detached from the opposed surface of each die plate. The work for fastening or unfastening the insert die to or from the main mold is performed outside the die casting machine before and after the mold changing operation so that total time of the mold changing operation can be reduced.

FIG. 4 shows a situation that a pair of main molds MVD and FXD is carried in a mold opened space together with the inserts by means of the crane and so on, after the upper tie bars TBU are pulled out.

Here, the mold opened space is defined as a space formed between both of the mounting surfaces on a moving die plate MVPL and a fix die plate FXPL when the moving die plate MVPL retracts from the fix die plate FXPL by a predetermined distance.

In FIG. 4 a reference code TBU designates the upper tie bar, and reference codes CYL 1, CYL 2 and CYL 3 designate cylinders for the cores which are mounted on the main mold MVD fastened on the mold mounting surface of the moving die plate MVPL. Reference codes MINS and FINS are a pair of insert dies fastened in the main mold MVD and the main mold FXD.

In FIG. 4 a die height is defined as the distance between both of the mold mounting surfaces when the moving die plate MVPL reaches a mold closing position in the direction of right under the condition that each of the main molds MVD and FXD is fastened on the mold mounting surface of the moving die plate and the fix die plate, respectively. In the figure, therefore, the die height is figured out as the sum of length of the main molds MVD and FXD in the direction of the tie bar axis. This die height is inherent in the combination of main molds MVD and FXD, that is, there necessarily exists a length inherent in another pair of main molds which differs in length from one pair of main molds. Accordingly, it is reasonable that the mold closing position can not be set less than the die height inherent in the main molds.

On the other hand, there is provided with a conventional type of die casting machines in which a toggle mechanism and a link housing (not shown) are mostly employed, or a conventional type of die casting machines in which a ram cylinder to clamp molds and a template to fasten the cylinder are arranged.

In these types of die casting machines, the dimension of a base BS, namely, the length of the mold clamping apparatus becomes considerably large in the direction of mold opening and closing, and also because it is necessary to extend the tie bar to a location of the link housing or the template, there causes a problem that the tie bar must be elongated and thickened.

Further, in the middle or large size of die casting machines, the die height of the molds becomes large and the weight reaches a few tons to more than ten tons. Particularly, bending moment always acts downward on the moving die plate MVPL which moves on a guide because of forming a cantilever that could be factors of turning over or tilting.

SUMMARY OF THE INVENTION

To solve the problems mentioned above, inventors of the present invention have devoted themselves to analyze, study, examine and make exertion, and then as the result, have taken into account that conventionally the main molds are fastened on the mold mounting surfaces of the die plates, and found out that the various problems could be basically solved by placing the main molds inside the respective die plates.

OBJECT OF THE INVENTION

Accordingly, a first object of the present invention is to provide a die plate for a die casting machine and so on capable of reducing die height as small as possible.

A second object of the present invention is to provide a mold clamping apparatus for the die casting machine and so on equipped with the die plate.

Further, a third object of the present invention is to provide a method of changing a mold in the die casting machine and so on using the mold clamping apparatus equipped with the die plate.

Further, a fourth object of the present invention is to provide a method of changing a moving die plate of the mold clamping apparatus equipped with the die plate in the die casting machine and so on.

Further, a fifth object of the present invention is to provide a changing system for implementing the method of changing the moving die plate.

Other objects of the present invention will be apparent in the following description.

Means for Solving the Problem

To achieve the first object, the die plate for the die casting machine and so on according to the present invention is constituted such that it places the main mold with versatility fastening and holding an insert die detachably.

In the case the main mold with versatility can be constituted such that it is detachably fastened and held inside the die plate.

Also, in the case the main mold with versatility can be constituted such that it is incorporated integrally inside the die plate, and at least a portion of a constituent member of the main mold with versatility is constituted so as to be a mechanical constituent member of the die plate. Further, in the case the die plate can be a moving die plate.

To achieve the second object, the mold clamping apparatus for the die casting machine and so on according to the present invention is constituted such that it comprises

-   -   a base,     -   a fix die plate standing fixedly on an end of an injection side         of the machine,     -   a moving die plate arranged so as to proceed and retract on the         base facing the fix die plate,     -   a guide means arranged on the base in order to guide proceeding         and retracting movement of the moving die plate,     -   a first drive means for allowing the moving die plate to proceed         and retract on the guide means,     -   a tie bar passing through a portion neighboring to a corner of         each die plate and acts so as to hold clamping state to both of         the die plates, and     -   a second drive means for producing clamping force between the         fix die plate and the moving die plate,     -   said each die plate being formed to place a main mold with         versatility inside, which fastens and holds an insert die         detachably.

In the case the first drive means can be provided with a threaded shaft rotated by a servomotor mounted on the base, a nut which slides on the guide means and screws together with the threaded shaft, and a fastening member fixedly fastened at a side face of the moving die plate

Also, in the case the second drive means can be provided with a clamp cylinder formed at a portion in the fix die plate through which the tie bar passes, a first fastening means provided in the fix die plate to fasten one end portion of the tie bar passing through the fix die plate and a second fastening means provided in the moving die plate to fasten the other end portion of the tie bar passing through the moving die plate.

To achieve the third object, a method of changing a mold in a die casting machine and so on according to the present invention is constituted such that, in a method of changing a mold of a die casting machine and so on provided with a mold clamping apparatus comprising a base, a fix die plate standing fixedly on an end of an injection side of the machine, a moving die plate arranged so as to proceed and retract on the base facing the fix die plate, a guide means arranged on the base in order to guide proceeding and retracting movement of the moving die plate, a first drive means for allowing the moving die plate to proceed and retract on the guide means, a tie bar passing through a portion neighboring to a corner of each die plate and acts so as to hold clamping state to both of the die plates, and a second drive means for producing clamping force between the fix die plate and the moving die plate, each die plate being formed to place a main mold with versatility inside, which fastens and holds an insert die detachably, the method comprises the steps of

-   -   forming a mold opened space between the moving die plate and the         fix die plate by retracting to a predetermined position the         moving die plate among the die plates placing respectively a         first main mold with versatility fastening a first insert die,         which corresponds to a first level of versatility and         constitutes a first mold in the state before mold changing         operation,     -   bringing out each of the first insert dies to the mold opened         space by unfastening the first insert die from the first main         mold with versatility,     -   carrying out each of the first insert dies brought out to the         mold opened space to a predetermined position, independently or         in the form of a pair of first insert dies,     -   preparing a pair of second insert dies corresponding to the         first level of versatility to a second predetermined position in         order to form a second mold in the state after mold changing         operation,     -   in the succeeding sequence, carrying in the pair of second         insert dies waiting at the second predetermined position to the         mold opened space,     -   forming the second mold by separating the pair of second insert         dies in the mold opened space and then fastening the separated         second insert to each of the first main mold with versatility,         and     -   proceeding the moving die plate to a mold closing position after         forming the second mold.

Further to achieve the fourth object, a method of changing a moving die plate of a mold clamping apparatus provided with a die plate according to the present invention is constituted such that, in a method of changing a moving die plate of a die casting machine and so on provided with a mold clamping apparatus comprising a base, a fix die plate standing fixedly on an end of an injection side of the machine, a moving die plate arranged so as to proceed and retract on the base facing the fix die plate, a guide means arranged on the base in order to guide proceeding and retracting movement of the moving die plate, a first drive means for allowing the moving die plate to proceed and retract on the guide means, a tie bar passing through a portion neighboring to a corner of each die plate and acts so as to hold clamping state to both of the die plates, and a second drive means for producing clamping force between the fix die plate and the moving die plate, said each die plate being formed to place a main mold with versatility inside, which fastens and holds an insert die detachably, the method comprises the steps of

-   -   forming a mold opened space between the moving die plate and the         fix die plate by retracting to a first predetermined position on         the base a first moving die plate arranged on the base and         placing a first main mold with versatility inside corresponding         to a first level of versatility using the first drive means, in         the state before moving die plate changing operation,     -   bringing out each of the insert dies to the mold opened space by         unfastening the respective insert die from the main mold with         versatility in each die plate,     -   carrying out each of the insert dies brought out to the mold         opened space, independently or in the form of a pair of first         insert dies,     -   then, further retracting the first moving die plate to a second         predetermined position,     -   preparing a second moving die plate, which places a second main         mold with versatility inside corresponding to a second level of         versatility differing from the first level of versatility, to a         predetermined waiting position,     -   in the succeeding sequence to further retracting, carrying out         the first moving die plate from the base,

then, carrying in the second moving die plate prepared in the predetermined waiting position to the second predetermined position.

Further to achieve the fifth object, a changing system of a moving die plate to implement the method of changing a moving die plate of a mold clamping apparatus provided with a die plate according to the present invention is constituted such that the changing system provides with

-   -   a first storage means for storing one or a plurality of moving         die plates placing a main mold with versatility inside         corresponding to different levels of versatility,     -   a second storage means for storing a plural pairs of insert dies         formed so as to use in accordance with each of the main molds         with versatility provided in the moving die plate,     -   a first conveying carriage for receiving the first moving die         plate from the second predetermined position on the base in the         step of carrying out the first moving die plate from the base,     -   a second conveying carriage for carrying in the second moving         die plate prepared in the predetermined waiting position in the         step of carrying in the second moving die plate prepared in the         predetermined waiting position to the second predetermined         position.     -   a first run for the first conveying carriage and the second         conveying carriage which is arranged at least between a vicinity         of the first storage means and a vicinity of the second         predetermined position, and     -   a conveying control unit for controlling movement of the first         and second conveying carriages on the first run.

In the case the waiting position for the second moving die plate can be located within the first storage means.

Also in the case the first run can be provided with a bypass arranged in the vicinity of the base, which is available as the waiting position.

Further in the case the moving die plate stored in the first storage means includes a first type of the moving die plate which places a main mold with versatility to be fasten and held detachably, and a second type of the moving die plate which places said main mold with versatility incorporated integrally inside and at least a portion of a constituent member of the main mold with versatility forming a mechanical constituent member of the moving die plate, or includes either one of the first type and the second type.

Further in the case a storage means of the first storage means for storing the first type of the moving die plate is located at a different position from that of a storage means of the first storage means for storing the second type of the moving die plate.

Further in the case the system is provided with an insert die mounting means which enables a pair of insert dies to carry in and carry out through a side portion of the die casting machine and so on.

Also the first, second and third conveying carriages are a type of automotive carriage.

(Effect of the Invention)

According to the present invention described in claim 1, because the main mold is placed inside the die plate the die height can be reduced as small as possible without depending on the kind of the mold clamping apparatus of the die casting machine and so on, and factors of turning over or tilting of the die plate due to the weight of the main mold including the insert die can be eliminated.

According to the present invention described in claim 7, in addition to the advantages described above, the mold clamping cylinder is formed at the side of the fix die plate and also, the work for pulling out and inserting the tie bar before and after the mold changing operation does not need. Accordingly, the cylinder for pulling out the tie bar is unnecessary. Further the length of the mold clamping apparatus in the direction of mold opening and closing can be ranged substantially within a range of movement of the moving die plate so that the tie bar can be shorten, thereby reducing production cost of the mold clamping apparatus and making it easy to maintenance.

According to the present invention described in claim 7, because the mold changing operation can be implemented by carrying in and carrying out one pair of insert dies it is possible to save the time required conventionally for pulling out and inserting the tie bar, thereby simplifying the mold changing operation.

According to the present invention described in claim 10, the moving die plate can be carried out the mold clamping apparatus through only moving it to the second predetermined position on the base without pulling out the tie bar, and further it is possible to change the moving die plate through only introducing next moving die plate placing the next main mold with versatility to the second predetermined position within the mold clamping apparatus.

According to the present invention described in claim 11, because the first storage means stores a plurality of moving die plates with different levels of versatility, it is possible to select a moving die plate placing a main mold with versatility having the level of versatility required in the next molding operation in advance, and to allow the moving die plate to wait in the vicinity of the mold clamping apparatus in the state of mounting it on the conveying carriage, thereby enabling the change of the moving die plate to terminate in a short time.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view illustrating whole of a mold clamping apparatus of a die casting machine according to the present invention.

FIG. 2 is a simplified view of mold changing in a mold clamping apparatus providing a die plate according to the present invention.

FIG. 3 illustrates an arrangement of a structure for changing system of a moving die plate according to the present invention.

FIG. 4 illustrates a state in which a pair of molds is carried in a mold opened space together with insert dies by a crane and so on for explaining a substantial portion of the conventional mold change.

FIG. 5 is a flow chart illustrating a series of conventional work sequences for mold changing operation.

DETAILED DESCRIPTION OF THE INVENTION

The preferred embodiment of the present invention will be explained below, referring to attached drawings of FIG. 1 to 3.

FIG. 1 is a side view illustrating whole of a mold clamping apparatus 100 of a die casting machine according to the present invention.

In FIG. 1 there is provided with a fix die plate FXPL standing fixedly at the right end portion of a base BS. On the lateral face of injection side of the fix die plate FXPL there is mounted a frame 104 shaped character U. An injection plunger rod (not shown) is inserted into a sleeve 102 through a hole provided in the vertical portion of the frame 104.

A moving die plate MVPL is arranged opposing the fix die plate FXPL.

Two upper tie bars TBU and Two lower tie bars TBD are arranged on both of the die plates in a way that those tie bars pass through at each comers of the respective die plates. A reference code TBSC is an engaging portion with the moving die plate MVPL, which is provided with a thread or a square groove in the circumferential surface. The engaging portion TBSC is engaged with an engaging member provided in a clamping device CLMP2 mounted on the side of the moving die plate MVPL opposed to the fix die plate when the tie bar TBU and each die plate are in a predetermined phase related position.

A reference code CLMP1 is a clamping device provided with an engaging member inside which engages with an engaging portion such as a thread or a square groove formed at an end portion on the fix die plate side of the tie bar TBU passing through the fix die plate FXPL.

A reference code CYL is a mold clamping cylinder formed at a portion of the fix die plate through which the tie bar TBU passes. The tie bar TBU is used as a piston and a piston rod for the mold clamping cylinder CYL. In addition, though a clamping device for the lower tie bar TBU is not shown and only an end portion on the fix die plate side of the tie bar TBD is shown, a similar clamping device is provided for the tie bar TBD. Also, a clamping device CLMP2 for the moving die plate MVPL is provided in a lower portion of the moving die plate for the tie bar TBD.

A reference numeral 10 is a mounting provided in the side of the base BS on which a servomotor SV is mounted. A reference numeral 16 is a ball screw shaft. A rotary encoder is mounted on the axis of the servomotor SV (not shown).

A reference numeral 12 is a nut screwed with the thread of the ball screw shaft, which is mounted on a connecting member 14. This connecting member 14 is slidably arranged on a guide 18 which bottom portion is arranged on the base BS. The connecting member 14 is provided with a side wall portion extending vertically from the bottom portion which is fastened to a side of the moving die plate MVPL.

These components 10, SVM, 16, 14, and 18 are also arranged on the base BS at the counter side to the front side of the machine where an operator usually stands.

In addition, those components constitute a first drive means of the present invention. Also, the clamping devices CLMP1 and CLMP2 constitute a second drive means of the present invention.

The clamping device CLMP1 becomes to the state allowing an engage portion of the engaging member of the clamping device CLMP1 to mate the thread or the square groove formed at the end portion of the tie bar TBU, when the end face of the tie bar TBU on the fix die plate side contacts with a member provided in the clamping device and the phase between the engage portion and the thread or the square groove coincides.

And then, by means of actuating the mold clamp cylinder CYL and moving the tie bar TBU in the direction of the axis in the state that the clamping device CLMP1 mates with the tie bar TBU, it is possible to adjust in a way that a phase of the thread or the square groove TBSC of the tie bar passing through the moving die plate MVPL coincides with a phase of the engage portion of the engaging member provided in the clamping device CLMP2.

In addition inventors have already studied in detail of mechanisms as to the mold clamping cylinder CYL and the clamping device CLMP1.

Accordingly, the engagement in the clamping device CLMP1 can be released only when a mold closing position of the moving die plate is changed, associated with the mold changing operation.

On the contrary, the engagement in the clamping device CLMP2 can be released each time when the moving die plate MVPL is proceeded and retracted by the first drive means. A reference numeral 20 designates the outer shape of a main mold with versatility placed inside the moving die plate MVPL.

FIG. 2 is a simplified illustration of a mold changing operation in the mold clamping apparatus provided with a die plate according to the present invention. As shown in FIG. 2, main molds with versatility MVD and FXD are placed inside moving die plate MVPL and fix die plate FXPL, respectively.

As illustrated in the figure, a pair of insert die INS which is formed by the insert dies FINS and MINS is carried in to a mold opened space without disturbing tie bar TBU or TBD located in an upper portion or a side portion. The pair of insert die is separated and fastened to each of the main molds with versatility MVD and FXD.

The die height becomes zero or very small when the moving die plate positions at a mold closing position, and as the result dimension of the mold clamping apparatus in the direction of mold opening and closing can be shortened. Also, there is no tilting in the moving die plate MVPL and the fix die plate FXPL due to the total weight when the main molds with versatility are fastened on the opposed surface of each die plate, as implemented conventionally.

Each insert dies MINS and FINS of the pair of the insert die INS can be carried in independently.

Though the pair of insert die INS can be carried in and carried out to and from the mold opened space using a crane, as shown in FIG. 3 it is also possible to transfer the pair of insert die INS in a way that using a conveying carriage CNV.B for only the insert die INS, a requested insert die INS stored in a storage 200 at a predetermined location is conveyed to a station 300B located aside the die casting machine DM1, and then the insert die INS on the carriage CNV.B is transferred to an insert die mounting means LD from the carriage CNV.B. In the case the insert die mounting means LD can be inserted into the mold opened space from the lateral direction.

This insert die mounting means LD can be provided with, for example, rolling means such as guide rails for guiding the insert die and rollers. Further the insert die mounting means LD can be provided with a guide means which guides the insert die positioned in a predetermined position of the mold opened space so that it moves in the direction of each die plate.

Though the detailed mechanism is not shown about attaching and fastening of the insert die INS to the main mold with versatility placed inside the moving die plate MVPL, it is possible to adopt, for example, a mechanical combining means such as a pull stud and a screw or a hydraulic mechanism in combination with the mechanical combining means.

In addition, in case of inserting the insert die MINS into the main mold with versatility MVD, the operator himself can plug the insert die MINS making sure by hand. But, it is also possible to pull in and pull out the insert die MINS by providing a pulling in and out means at the main mold MVD.

It is possible, but not effective that as to the main mold with versatility MVD placed inside the moving die plate MVPL, a single main mold with versatility corresponds to all the insert die used in the die casting machine. Namely, the main mold can be classified by three ranks of large, middle and small in accordance with the size of molded articles which the die casting machine can molds, and the main molds in accordance with each ranks of large, middle and small can be prepared. Thus, by setting kinds or ranks for the main mold with versatility it is possible to avoid forming the insert die to be needlessly large size, because material for the insert die is expensive

In the present invention the kind of the main mold with versatility is defined as a level of versatility. As mentioned above, the level of versatility can be defined by not only the size of the insert die, but also complexity of the mechanism in the main mold with versatility.

Also, the level of versatility can be defined by combination of the size and the complexity.

On the other hand, the main mold with versatility FXD placed inside the fix die plate FXPL, as described previously, is usually formed much simpler than the main mold with versatility MVD of the moving die plate MVPL. Therefore it is not necessarily to be identical to the level of versatility of the main mold with versatility MVD. Namely, the main mold with versatility FXD can be formed as a main mold with much higher level of versatility so that it has plural levels of versatility.

In the case, though the insert die FINS inserted and fastened can be formed to correspond to each level of versatility, the insert die FINS can correspond to the main mold with higher level of versatility FXD in the fix die plate by intervening an adjusting member among the insert die FINS and the main mold FXD. In the case the adjusting member can be prepared so as to correspond to each level of versatility.

Next, a configuration will be explained for placing the main mold with versatility MVD which is also placed inside the moving die plate MVPL.

This main mold with versatility MVD can be largely classified to two cases.

The one is the case that the main mold with versatility MVD can be formed so as to easily separate from the moving die plate MVPL by unfastening the main mold MVD itself though it is usually fastened and held in the moving die plate MVPL.

The other is the case that at least a portion of a constituent member forming the main mold with versatility MVD is a mechanical constituent member of the moving die plate MVPL, which is rather incorporated integrally, thereby structurally constituting a part of the moving die plate MVPL. In such cases, in the present invention the moving die plate placing the former main mold with versatility is defined as a first type of moving die plate and the moving die plate placing the latter main mold with versatility is defined as a second type of moving die plate.

As apparently seen from FIG. 2, in case that the moving die plate MVPL is the first type, even if the main mold is unfastened, it is impossible to carry out the main mold from the mold opened space, because of the tie bars TBU and TBD. Also, in case of the main mold with versatility MVD in the second type of the moving die plate, it is even more so.

In the present invention, as a correspondence to the case that a main mold with one level of versatility placed inside the first type of moving die plate is changed to another main mold with different level of versatility, the following procedure is implemented. Namely, the moving die plate MVPL as shown in FIG. 1, after the insert die is pulled out and then the engagement with the tie bar TBU in the clamping device CLMP2 is released, is moved further to the left, that is, to the end portion of the base BS which is a predetermined retracting position by the first drive means equipped with the servomotor SVM. Then the moving die plate MVPL is transferred on a first conveying carriage waiting at a first position in the vicinity of the base end portion, thereby carrying it out outside the mold clamping apparatus of the die casting machine. Then, a second conveying carriage, which mounts another moving die plate placing a main mold with a newly requested level of versatility, and preliminarily waits at a different second position in the vicinity of the base end portion, is moved to the first position and then transfers another moving die plate on the base, thereby changing the moving die plate.

FIG. 3 illustrates an arrangement of a structure for changing system of a moving die plate according to the present invention.

In FIG. 3 reference codes DM1 and DM2 are die casting machines provided with a mold clamping apparatus according to the present invention. A reference numeral 200 is a storage means including a first storage means 200A which stores a plurality of moving die plates and a second storage means 200B which stores a plurality pair of insert die INS.

Though the first storage means 200A can store both of the first type and the second type of the moving die plates, the first type of the moving die plate may be stored in a storage means 400 which is located independently.

A reference numeral 500A is a run for a conveying carriage CNV.A which mounts the moving die plate MVPL. This run 500A is provided with a bypass run for accessing the storage means 400. On the bypass run the conveying carriage CNV.A for waiting are located as shown in the figure. A reference numeral 300A is a station for transferring the moving die plate, arranged in the vicinity of the end portion of the base of the mold clamping apparatus. In FIG. 3 the first conveying carriage CNV.A positioned at the right side of the second conveying carriage CNV.A at the left side does not yet mount the moving die plate. So, the first conveying carriage approaches the station 300A in which it receives the moving die plate for carrying out that preliminarily waits.

A reference numeral 500B is a run for the insert die INS. This run 500B is arranged between the second storage means 200B and the station 300B located in the vicinity of the mold opened space on one side of the mold clamping apparatus of the die casting machine DM1. A reference code CNV.B is a third conveying carriage which mounts the insert die INS and conveys on the run 500B. The detail of carrying in and carrying out the insert die between the insert mounting means LD and each main mold with versatility is omitted because of previously described.

A reference numeral 600 is a carriage control unit for controlling conveying position of the conveying carriages CNV.A and CNV.B. Each conveying carriage may be an automotive carriage or a type of carriage driven by external force such as a chain and hydraulic cylinder. A reference code SG1 is a receiving signal such as the conveying position from each conveying carriage, and reference code SG2 is a control signal supplied to each conveying carriage.

Though a preferred embodiment of the present invention is explained in the case of the die casting machine, it should be understood that a person with ordinary skilled in the art could easily apply the present invention to the mold clamping apparatus of the plastic injection molding machine provided with a similar mold clamping apparatus. 

1. A die plate for a die casting machine and so on which places a main mold with versatility fastening and holding an insert die detachably.
 2. A die plate for a die casting machine and so on according to claim 1 wherein said main mold is detachably fastened and held in the die plate.
 3. A die plate for a die casting machine and so on according to claim 1 wherein said main mold with versatility is incorporated integrally inside the die plate and at least a portion of a constituent member of the main mold with versatility forms a mechanical constituent member of the die plate.
 4. A die plate for a die casting machine and so on according to any one of claim 1 to 3 wherein said die plate is a moving die plate.
 5. A mold clamping apparatus for a die casting machine and so on comprising a base, a fix die plate standing fixedly on an end of an injection side of the base, a moving die plate arranged so as to proceed and retract on the base facing the fix die plate, a guide means arranged on the base in order to guide proceeding and retracting movement of the moving die plate, a first drive means for allowing the moving die plate to proceed and retract on the guide means, a tie bar passing through a portion neighboring to a corner of each die plate and acts so as to hold clamping state to both of the die plates, and a second drive means for producing clamping force between the fix die plate and the moving die plate, said each die plate being formed to place a main mold with versatility inside, which fastens and holds an insert die detachably.
 6. A mold clamping apparatus for a die casting machine and so on according to claim 5, wherein said first drive means comprises a threaded shaft rotated by a servomotor mounted on the base, a nut which slides on the guide means and screws together with the threaded shaft, and a fastening member fixedly fastened at a side face of the moving die plate.
 7. A mold clamping apparatus for a die casting machine and so on according to claim 5 or 6, wherein said second drive means comprises a clamp cylinder formed at a portion in the fix die plate through which the tie bar passes, a first fastening means provided in the fix die plate to fasten one end portion of the tie bar passing through the fix die plate and a second fastening means provided in the moving die plate to fasten the other end portion of the tie bar passing through the moving die plate.
 8. A mold clamping apparatus for a die casting machine and so on, according to claim 5, wherein said first and second drive means comprise a toggle mechanism and a link housing connected to a counter side of the moving die plate facing the fix die plate.
 9. A method of changing a mold in a die casting machine and so on provided with a mold clamping apparatus comprising a base, a fix die plate standing fixedly on an end of an injection side of the base, a moving die plate arranged so as to proceed and retract on the base facing the fix die plate, a guide means arranged on the base in order to guide proceeding and retracting movement of the moving die plate, a first drive means for allowing the moving die plate to proceed and retract on the guide means, a tie bar passing through a portion neighboring to a corner of each die plate and acts so as to hold clamping state to both of the die plates, and a second drive means for producing clamping force between the fix die plate and the moving die plate, said each die plate being formed to place a main mold with versatility inside, which fastens and holds an insert die detachably, said method comprising the steps of forming a mold opened space between the moving die plate and the fix die plate by retracting to a predetermined position the moving die plate among said die plates placing respectively a first main mold with versatility fastening a first insert die, which corresponds to a first level of versatility and constitutes a first mold in the state before mold changing operation bringing out each of said first insert dies to the mold opened space by unfastening the first insert die from the first main mold versatility, carrying out each of said first insert dies brought out to mold opened space to a predetermined position, independently or in the form of a pair of first insert dies, preparing a pair of second insert dies corresponding to the first level of versatility to a second predetermined position in order to form a second mold in the state after mold changing operation, in the succeeding sequence, carrying in the pair of second insert dies waiting at the second predetermined position to the mold opened space, forming said second mold by separating the pair of second insert dies in the mold opened space and then fastening the separated second insert to each of the first main mold with versatility, and proceeding the moving die plate to a mold closing position after forming said second mold.
 10. A method of changing a moving die plate for changing a main mold with versatility provided in the moving die plate to another main mold with versatility in a die casting machine and so on provided with a mold clamping apparatus comprising a base, a fix die plate standing fixedly on an end of an injection side of the machine, a moving die plate arranged so as to proceed and retract on the base facing the fix die plate, a guide means arranged on the base in order to guide proceeding and retracting movement of the moving die plate, a first drive means for allowing the moving die plate to proceed and retract on the guide means, a tie bar passing through a portion neighboring to a corner of each die plate and acts so as to hold clamping state to both of the die plates, and a second drive means for producing clamping force between the fix die plate and the moving die plate, said each die plate being formed to place a main mold with versatility inside, which fastens and holds an insert die detachably, said method comprising the steps of forming a mold opened space between the moving die plate and the fix die plate by retracting to a first predetermined position on the base a first moving die plate arranged on the base and placing a first main mold with versatility inside corresponding to a first level of versatility using said first drive means, in the state before moving die plate changing operation, bringing out each of said insert dies to the mold opened space by unfastening the respective insert die from the main mold with versatility in each die plate, carrying out each of said insert dies brought out to the mold opened space, independently or in the form of a pair of first insert dies, then, further retracting the first moving die plate to a second predetermined position, preparing a second moving die plate, which places a second main mold with versatility inside corresponding to a second level of versatility differing on the first level of versatility, to a predetermined waiting position, in the succeeding sequence to said further retracting, carrying out the first moving die plate from the base, then, carrying in the second moving die plate prepared in the predetermined waiting position to the second predetermined position.
 11. A changing system of a moving die plate for implementing the method of changing a moving die plate according to claim 10, comprising a first storage means for storing one or a plurality of moving die plates placing a main mold with versatility inside corresponding to different levels of versatility, a second storage means for storing a plural pairs of insert dies formed so as to use in accordance with each of the main molds with versatility provided in the moving die plate, a first conveying carriage for receiving the first moving die plate from the second predetermined position on the base in said step of carrying out the first moving die plate from the base, a second conveying carriage for carrying in the second moving die plate prepared in the predetermined waiting position in said step of carrying in the second moving die plate prepared in the predetermined waiting position to the second predetermined position. a first run for the first conveying carriage and the second conveying carriage which is arranged at least between a vicinity of the first storage means and a vicinity of the second predetermined position, and a conveying control unit for controlling movement of the first and second conveying carriages on the first run.
 12. A changing system of a moving die plate in a die casting machine and so on according to claim 11, wherein a waiting position for the second moving die plate is located within the first storage means.
 13. A changing system of a moving die plate in a die casting machine and so on according to claim 11, wherein said first run is provided with a bypass arranged in the vicinity of the base, which is available as the waiting position.
 14. A changing system of a moving die plate in a die casting machine and so on according to claim 11, wherein said moving die plate stored in the first storage means includes a first type of the moving die plate which places a main mold with versatility to be fasten and held detachably, and a second type of the moving die plate which places said main mold with versatility incorporated integrally inside and at least a portion of a constituent member of the main mold with versatility forming a mechanical constituent member of the moving die plate, or includes either one of the first type and the second type.
 15. A changing system of a moving die plate in a die casting machine and so on according to any one of claims 11 to 14, wherein a storage means of the first storage means for storing the first type of the moving die plate is located at a different position from that of a storage means of the first storage means for storing the second type of the moving die plate.
 16. A changing system of a moving die plate in a die casting machine and so on according to claim 11, wherein said system is provided with an insert die mounting means which enables a pair of insert dies to carry in and carry out through a side portion of the die casting machine and so on.
 17. A changing system of a moving die plate in a die casting machine and so on according to claim 11, wherein said system is provided with a second run arranged between the second storage means and the side portion of the die casting machine and so on and on which the pair of the insert dies is conveyed, and a third conveying carriage for conveying the pair of the insert dies on the second run.
 18. A changing system of a moving die plate in a die casting machine and so on according to claim 11, wherein said first, second and third conveying carriages are a type of automotive carriage. 